Electrohydraulic Control Jack for Variable Compression Ratio
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Solution Overview
Problem
The control of variable compression ratio engines is hindered by large diameter control jacks, reduced operating pressure, increased space and weight requirements, and the difficulty in independently controlling each cylinder's compression ratio due to the need for multiple electric actuators and complex transmission means.
Innovation Solution
An electrohydraulic device with electrovalves, position sensors, and a computer system that eliminates the control rod and associated components, reducing the diameter of the jack piston and eliminating the need for electric motors, allowing for independent regulation of each cylinder's compression ratio through hydraulic fluid management between the top and bottom chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a control rod with valves and springs is used to control the compression ratio, then the compression ratio can be regulated, but the diameter of the control jack increases and the operating pressure decreases
Solution Approach 1:
The patent removes the control rod, valves, and springs from the control jack assembly. Instead, it uses a simplified piston-cylinder arrangement where the piston directly responds to hydraulic pressure to move the control rack, thereby eliminating the bulky valve mechanism while maintaining compression ratio control capability
Solution Approach 2:
The patent replaces the mechanical valve-spring system with a direct hydraulic actuation system. The piston is directly acted upon by hydraulic pressure from the hydraulic unit, eliminating the need for mechanical valves and springs, which reduces the diameter and allows higher operating pressures
2Adaptability or versatility
If multiple electric actuators are used to independently control each cylinder's compression ratio, then independent control is achieved, but the space and weight requirements increase
Solution Approach 1:
The patent employs a single hydraulic unit that serves multiple cylinders through a common hydraulic circuit. The hydraulic piston can be selectively actuated to control the compression ratio of different cylinders, eliminating the need for separate electric actuators for each cylinder while maintaining independent control capability
Solution Approach 2:
The patent uses a hydraulic system with a common hydraulic unit and circuit that can independently control multiple cylinders. The hydraulic fluid can be directed to different cylinders as needed, providing multi-functionality with a single actuator system, thereby reducing overall system weight compared to multiple electric actuators
3Measurement precision
If a control rod with valves is used, then compression ratio regulation is achieved, but the space requirement and weight of the control jack assembly increase
Solution Approach 1:
The patent extracts and removes the control rod, valves, and springs from the control jack assembly. The simplified piston-cylinder arrangement occupies significantly less space while maintaining the ability to precisely regulate compression ratio through direct hydraulic actuation
Solution Approach 2:
The patent replaces the bulky mechanical valve-spring system with a compact direct hydraulic actuation system. The piston directly responds to hydraulic pressure without intermediate mechanical components, reducing the overall volume of the control jack assembly while preserving regulation precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces the space, weight, and cost of the engine while enhancing responsiveness and precision in controlling the compression ratio, allowing for efficient and precise regulation of each cylinder's compression ratio.
Implementation Method 1
The control jack comprises a top chamber and a bottom chamber which are in communication with each other through a duct arranged in the piston of the jack
Data Source
AI summary
An electrohydraulic device for controlling the compression ratio of a variable compression-ratio engine, includes at least one dual-flow electrovalve with no check valve and capable of opening and closing at least one hydraulic fluid duct between an upper chamber and a lower chamber of a control jack, at least one position sensor of a control rack, an angular position sensor of the crankshaft of the engine for adjusting the compression ratio, and at least one calculator.